Object in Cycles is getting illuminated but stays black in Eevee
I could narrow it down to the huge number of lights (134) in the scene.
Deleting all lights and adding a fresh sun restores the display of shadows. By using the new filtering parameters, lights can easily be found:  

It looks like that eevee cant handle that many lights and additional ones will simply be ignored:  https://docs.blender.org/manual/en/latest/render/eevee/limitations.html